Direct air-brake system.



A. DOAN.

DIRECT AIR BRAKE SYSTEM.

APPLICATION FILED APR.1. 1909.

Patented Marf 15, 1910.

INVENTOR ARTHUR DOAN WlTNESSES! HIS ATTORNEY.

ANDREW a GRAHAM co PHUYO-LITNDGWNERS, wnsamamn. n. c.

ARTHUR DOAN, OF OAKLAND, CALIFGRNIA.

DIRECT AIR-BRAKE SYSTEM.

earner.

Specification of Letters Patent.

Application filed April 1, 1909.

Patented Mar. 15, 1910. Serial No. 487,157.

To all whom it may concern:

Be it known that I, ARTHUR Donn, citizen of the United States, residingat- Oakland, in the county of Alameda and State of California, haveinvented new and useful linprovements in Direct Air-Brake Systems, of

which the following is a specification.

My invention relates to air-brake systems for railway service, andpertains especially to an automatic auxiliary attachment.

There are two generally recognized systems of air-brake control, oneknown as the straight air, and the other as the automatic. The ordinarystraight air system takes the air direct from the main reservoir orreservoirs on the engine, through the train-line and delivers it intothe brake cylinders, without the use of any auxiliary reservoirs ortriple valves on the cars. The chief objection to this system is thedanger of the train breaking in two and allowing it to run away, becausewhen the connections are interrupted with the main reservoir 011 theengine, in such a system, there is nothing to operate the brakes. In theautomatic system, a triple valve and auxiliary reservoir is employed oneach car, with suflicient reserve pressure generally maintained in theauxiliary to operate the brakes.

I have designed a system in which I combine with the usual and simplestraight air system, an auxiliary system which does away with the triplevalve and employs a special arrangementof mechanism whereby on anythinggoing wrong with the air in the main reservoir or pumps, or the trainbreaking in two, the brakes will be set automatically. My system isapplicable alike to freight or passenger trains, and may be operated bythe usual signal line.

The invention consists of the parts and the construction and combinationof parts as hereinafter more fully described and claimed, havingreference to the accompanying drawings, in which Figure 1 is adiagrammatic representation in elevation and partial section of mysystem. Fig. 2 is a sectional view of a suitable form of three-way cock.

A represents the usual pump, and 2 the main reservoir, both located onthe engine.

3 represents a straight air line leading from the reservoir, andconnected acrossthe gaps between the cars by the usual flexible coupling4.

5 is an air-brake cylinder operated from the straight air line 3 throughthe branch pipe 6 and the three-way valve 7. The passage of the air fromthe reservoir 2 into the straight air line 3 is suitably controlled bythe usual engineers valve 8.

In ordinary running, to set the brakes, the engineer throws the valve 8to allow the air to pass into the straight air line 3, and thencethrough the normally open valve 7 to the brake cylinder 5. When it isdesired to release the brakes, the valve 8 is turned in the oppositedirection, and exhaust takes place through a pipe 9 beneath the engine.

So much of the mechanism thus far described represents the straight ordirect air system.

Connecting with the main reservoir 2 is a pipe 10 by which the air isled into the auxiliary line 11 through a regulating valve or governor 12and a three-way cook or valve 18. The gaps in the line 11 between thecars are bridged by a hose coupling 14 similar to coupling 4.

15 is an auxiliary reservoir on a car, connecting with the auxiliaryline 11 by a pipe 16 in which are disposed the check-valves 17. If thepressure in the main reservoir 2 is 150 or 200 pounds, more or less, itis designed that the reservoir 15 should contain a constant pressure ofsay 75 to 100 pounds; this pressure in the reservoir 15 being controlledby the governor 12. The reservoir 15 is also connected with the brakecylinder 5 by a pipe 18, but the flow of air from reservoir 15 to thebrake cylinder 5 is normally cut oil by means of the three-way valve 7,since it is only designed to operate the cylinder from the auxiliary 15when the air in the straight line pipe 3 fails, or the train breaks intwo, or something else goes wrong with the system.

Leading out from the cylinder or reservoir 15 is a small pipe 19 whichtaps the valve casing 20, in which is a port 21 lead ing into a cylinder22 on top of the piston 23. The stem 24 of piston 23 extends down by theair passing through a suitable stuffing-box in the lower end of cylinder22 and connects with lever 25 on the stem of the three-way cock 7. Aspring 26 acts on the under side of piston 28 normally to hold it up andkeep open valve 7 so that the straight line pipe 6 will ordinarily be incommunication with the brake cylinder,

at the same time cutting off communication between the latter and theauxiliary 15. This spring is particularly employed to insure the piston23 being held up so as not to turn oil the valve 7, and in case it isnecessary or desired to cut out the auxiliary at any time by thenormally open cock 19.

The port 21 is controlled by a needle valve 27- carried by a piston 28which works in a cylinder 29 formed in the casing 20. The space on theunder side of each of the pistons 23 and 28 is in constantconnnunication through the branch pipes 30 and pipe 31 with theauxiliary line 11, and the pres sure of the air in this auxiliary lineis effective ordinarily to lift both pistons 23 and 28, the one to turnthe valve 7 so as to cut out the auxiliary reservoir 15 from the brakecylinder, and. the other piston 28 operative to close port 21.

In practice, the auxiliary reservoir 15 is maintained normally chargedat a pressure suiiicient to operate the brake cylinder in case of need.Ordinarily, though, this auxiliary system is not called into use exceptwhen something goes wrong with the pump, or the train breaks in two;under all other conditions the brake cylinder being operated through theair from the straight line pipe 3 by suitably manipulating the engineersvalve 8. In case an emergency arises where the straight air line fails,then either by turning the lever 13 to allow exhaust to take place tothe atmosphere through a port 32, or in case the train breaks in two, soas to reduce the pressure in the auxiliary line 11, then, and in thatevent, the pressure being reduced on the under side of the pistons 28and 23, allows the air from the auxiliary to pass in on top of piston23, forcing the latter down, turning valve 7, and cutting oficommunication between the brake cylinder and pipe 6, and openingcommunication between the brake cylinder and auxiliary 15 and thereuponthe air passing from the auxiliary to the brake cylinder operates thebrakes.

Itis to be observed that I do not use a triple valve in this system, butby a combination of the straight line and my auxiliary system I obtainan automatic system which is very simple, and which, moreover, possessesthe desired requisites of safety.

Under some circumstances the auxiliary line 11 may be used for thesignal line, and the signal mechanism in the cab (not necessary here tobe shown) may be operated from alever 83; thus rendering the system ofautomatic signals from the train to the cab applicable on freighttrains.

Having thus described my invention, what I claim and desire to secure byLetters Patent is 1. The combination in an airvbrake system, of a mainreservoir, a brake cylinder, a. straight line connection between thebrake cylinder and said reservoir, a threeway valve and an engineersvalve in said connections, an auxiliary line connected with the mainreservoir, a supplemental reservoir connected therewith, and mechanismcontrolled by the difference in pressure between the auxiliary line andthe auxiliary reservoir, said mechanism being normally connected withthe three-way valve and operating said threeway valve so as to cut outthe straight line connection and connect the auxiliary reservoir withthe brake cylinder.

in an air-brake system, the combination of two air lines connectedtherewith, a brake cylinder connected with each air line, a three-wayvalve in said last-named connections and operative to connect the brakecylinder with one or the other of said lines, one of said linesconnected with an auxiliary reservoir, and fluid-controlled mechanismfor operating said three-way valve, said mechanism including a springpressed piston subjected to fluid pressure and a lever on the three-wayvalve connected to said piston.

3. In an air-brake system, the combination of a main reservoir, a brakecylinder, a straight air line connection between the brake cylinder andmain reservoir, an engineers valve and a threeway cock in saidconnections, an auxiliary line connected with the main reservoir, anauxiliary reservoir with which said auxiliary line connects, a governorvalve and a three-way valve in the auxiliary line, connections betweenthe auxiliary reservoir and the brake cylinder through said three-waycock, and mechanism for actuating said threeway cock operative throughthe dilierence in pressure between the auxiliary line and the auxiliaryreservoir.

In testimony whereof I have hereunto set my hand in presence of twosubscribing wit- ARTHUR DOAN.

nesses.

Witnesses:

CHARLES A. Penman), CHAnLns EDELMAN.

